/*
 * Copyright 2020-2022 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package graphql.solon.support;

import graphql.ExecutionResult;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.function.Consumer;


/**
 * {@link org.springframework.graphql.GraphQlResponse} implementation for server
 * handling over HTTP or over WebSocket.
 *
 * @author Rossen Stoyanchev
 * @since 1.0.0
 */
public class WebGraphQlResponse extends DefaultExecutionGraphQlResponse {

    private final Map<String, List<String>> responseHeaders;


    /**
     * Create an instance that wraps the given {@link ExecutionGraphQlResponse}.
     *
     * @param response the response to wrap
     */
    public WebGraphQlResponse(ExecutionGraphQlResponse response) {
        super(response);
        this.responseHeaders = new HashMap<>();
    }

    private WebGraphQlResponse(WebGraphQlResponse original, ExecutionResult executionResult) {
        super(original.getExecutionInput(), executionResult);
        this.responseHeaders = original.getResponseHeaders();
    }


    /**
     * Return the headers to be added to the HTTP response.
     * <p>By default, this is empty.
     * <p><strong>Note:</strong> This is for use with GraphQL over HTTP requests
     * but not for GraphQL over WebSocket where the initial handshake HTTP
     * request completes before queries begin.
     */
    public Map<String, List<String>> getResponseHeaders() {
        return this.responseHeaders;
    }

    /**
     * Transform the underlying {@link ExecutionResult} through a {@link Builder}
     * and return a new instance with the modified values.
     *
     * @param consumer callback to transform the result
     * @return the new response instance with the mutated {@code ExecutionResult}
     */
    public WebGraphQlResponse transform(Consumer<Builder> consumer) {
        Builder builder = new Builder(this);
        consumer.accept(builder);
        return builder.build();
    }


    /**
     * Builder to transform a {@link WebGraphQlResponse}.
     */
    public static final class Builder extends
        DefaultExecutionGraphQlResponse.Builder<Builder, WebGraphQlResponse> {

        private Builder(WebGraphQlResponse original) {
            super(original);
        }

        @Override
        protected WebGraphQlResponse build(WebGraphQlResponse original, ExecutionResult newResult) {
            return new WebGraphQlResponse(original, newResult);
        }

    }

}
